The invention concerns a gun barrel with a gun barrel liner and a breech ring, which are joined with each other by a bayonet thread, wherein a continuous cavity is left between adjacent bayonet ridges of the gun barrel liner and the bayonet ridges of the breech ring that are located axially behind them or in front of them.
In large-caliber gun barrels, the breech ring, which contains the breech mechanism, is usually screwed onto the rear-end region of the gun barrel liner to make it possible, when necessary, to change the gun barrel. In previously known gun barrels, in order to prevent, especially when a bayonet screw joint (DE 199 18 303 C2) is being used, unintentional unscrewing of the liner from the breech ring and in order to transmit to the breech ring the spin torques that develop during firing from a rifled barrel, the gun barrel liner is provided with a groove, into which a feather key fits, which feather key is installed in the breech ring of the gun.
A disadvantage associated with the use of this type of locking mechanism is that the groove milled into the gun barrel liner for transmitting the torque to the breech ring causes weakening of the liner, so that the service life of the liner is reduced or the tube outside diameter of the gun barrel liner must be selected larger than for liners without a groove of this type.